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The structure of macrozoobenthos assemblages in the area of sewage-treatment plant in Jurata - Jastarnia (the Puck Bay coastal zone)

100%

Obolewski K. , Jarosiewicz A.

tom Vol. 35, no. 4

91-103

Single study on horizontal distribution of macrozoobenthos in the sandy bottom of Jastarnia and Jurata coastal zone was conducted in summer 2004. 15 sampling sites in Jurata were divided into 4 radii every 100 m and 4 sampling sites were located near the harbor in Jastarnia. 18 species and 3 groups represented benthic invertebrates in the studied area. They reached the density of x = 1840 indiv.źm^-2 and wet mass of x = 121.8 gźm-2 near Jurata and near Jastarnia x = 638 indiv.źm^-2 and x = 376.6 gźm^-2, respectively. The most abundant species were Hediste diversicolor, Cerastoderma glaucum and Hydrobia ulvae. As for the biodiversity calculated with the Shannon index, it reached the highest values at sampling sites the most distant from the shore in Jurata. Species composition as well as qualitative and quantitative structure of benthic fauna in the studied area indicated unsatisfactory environmental conditions and low value of the area as a feeding ground for fish.

Badania nad poziomym rozmieszczeniem makrozoobentosu piaszczystego dna w okolicach Jastarni i Juraty prowadzone były jednorazowo latem 2004 roku. Wyznaczono 15 stanowisk w okolicach Juraty dzieląc stanowiska na cztery promienie oddalone od siebie o 100 m oraz 4 stanowiska w pobliżu portu w Jastarni. Bezkręgowce denne na tym obszarze reprezentowane były przez 18 gatunków i 3 grupy ponadgatunkowe, które w pobliżu Juraty osiągały zagęszczenie x = 1840 osobn.źm^-2 i masę mokrą x = 121,8 g_mmźm^-2, a w okolicach Jastarni x = 638 osobn.źm-2 i x = 376,6 g_mmźm^-2. Najczęściej spotykanymi gatunkami były Hediste diversicolor, Cerastoderma glaucum i Hydrobia ulvae. Większą bioróżnorodnością wyznaczoną wskaźnikiem Shannona-Wienera charakteryzowały się stanowiska najbardziej oddalone od brzegu w Juracie. Skład gatunkowy oraz struktura jakościowo-ilościowa fauny dennej w tej części Zatoki Puckiej świadczy o niezadowalającym stanie środowiska oraz niskiej wartości tych obszarów jako miejsca żerowania ryb.

Fluvial processes under late Pleni-Weichselian environmental conditions: a case study from the Warenka site in central Poland

80%

Petera-Zganiacz J. , Brzozowicz D. , Pawłowski D. , Kaczmarek P.

2024

tom Vol. 30, No. 2

81--94

Strong aggradational tendencies during the late Pleni-Weichselian have been noted in river valleys in central Europe. Thick series of mineral deposits were laid down, but also organic or mineral-organic horizons were formed under favourable conditions. The study area is located in the central section of the valley of the River Warta within an extraglacial area of the last glaciation. At the Warenka site alluvia, that attain thicknesses of 16 m, were analysed. Lithofacies analysis, OSL dating of mineral sediments and radiocarbon dating of organic and mineral-organic strata were performed. Organic and mineral-organic deposits were also subjected to pollen and Cladocera analyses. Together this set of analyses was used to determine fluvial processes and environmental conditions during the late Pleni-Weichselian. The results obtained allow the conclusion that these levels were deposited in the sedimentary environment of a low-energy, sand-bed braided river, which operated in the period from approximately 30 to 24 cal kBP – the late Pleni- Weichselian. During this time, there were periods when shallow water bodies were formed on the valley bottom, where deposition of organic material was possible. The presence of this type of sediment made it possible to reconstruct the vegetation cover; this had the character of a steppe-tundra, periodically shrubby steppe-tundra. Short-lived reservoirs were characterised by shallow-water settings with weakly developed vegetation and temporary influence of floodwaters as indicated by changes in cladoceran assemblages. Pollen spectra, low concentration of cladocerans, as well as the presence of the cold-tolerant Cladocera taxa are indicative of cold climatic conditions.